3:73 gears

[03stang0289]

i have an 03 5speed gt. Im putting in 3:73 gears . what will my rpm be on the highway at 65 mph? it runs at about 1500 rpm at 65mph now. what will it go up to?

 

[Sonic04GT]

What size rear tires do you have? There are different factors that play into this.

For example, I run 295/35/18:

MPH = 65
Tire Diameter = 26.12
Rear Gear Ratio = 3.73:1
Trans Gear Ratio = .68:1 (5th gear, 1:1 for 4th)
So in theory I would be at 2120.79 RPMs

Someone feel free to chime in if my figures are incorrect.

 

[03stang0289]

stock 275 45 17 . is that your car in the pic? i like the color!

 

[peepeeskillz]

with 4.10s im at about 2k at 60mph, so 3.73s should be less maybe 1700-1800?

 

[03stang0289]

how do you like the 4;10 on the highway? i get on the highway pretty often so i went with the 3:73 wondering if i should have went with 4:10

 

[Sonic04GT]

stock 275 45 17 . is that your car in the pic? i like the color!

With a 275/45/17 tire, theoretically you should be at...

2072 RPMs in 5th gear

or

2344 RPMs in 4th gear @ 50mph

 

[sneaky98gt]

with 4.10s im at about 2k at 60mph, so 3.73s should be less maybe 1700-1800?

Dang, is there that big of a difference in the stick and auto tranny overdrives? I'm a bit over 1800 at 60 and I have the stock 3.27s....

 

[peepeeskillz]

Dang, is there that big of a difference in the stick and auto tranny overdrives? I'm a bit over 1800 at 60 and I have the stock 3.27s....

with stock 3.27s i was at 1550 at 60mph thats with a TR3650 trans tho, 01 and older cars are different.

and on the highway its not that bad at 80mph its at about 2700, doesnt seem that high since my old car, and both my moms and my sisters car are at or over 3000 at 80.

 

[03ghoststang]

well if u are planning on doing future mods and/or considering a S/C then go with what will benefit u later..............but if staying N/A then 4.10's not that bad if you stay off the throttle

 

[ChillPhatCat]

with stock 3.27s i was at 1550 at 60mph thats with a TR3650 trans tho, 01 and older cars are different.

and on the highway its not that bad at 80mph its at about 2700, doesnt seem that high since my old car, and both my moms and my sisters car are at or over 3000 at 80.

But they're driving 4 bangers no? V8's are more intended to cruise around 2k whereas 4cy's are designed to cruise around 3k rpm. Not saying it's harmful, it's just not where they're terribly efficient. Obviously a higher gear ratio will hurt gas mileage no matter the car.

 

[midnightdriver]

I had 3.73's in my 85 K5 blazer with the turbo 400 trans and my rpms were about 2800 at 75 mph. It didn't seem to mind it, just sounded like you needed another gear.

 

[peepeeskillz]

But they're driving 4 bangers no? V8's are more intended to cruise around 2k whereas 4cy's are designed to cruise around 3k rpm. Not saying it's harmful, it's just not where they're terribly efficient. Obviously a higher gear ratio will hurt gas mileage no matter the car.

yea my sisters car is a 4 banger integra, but my moms car has a v6. my old car was an old 94 LS400 with a 4.0 v8 and it was about the same rpm as i am right now with 4.10s, but it did have an auto

i do notice having to give it more gas with 4.10s at highway speed compared to 3.27s just to cruise, but i dont know how much my mileage is actually effect since i dont do alot of highway driving, in the city so far my mileage was the same as 3.27s

 

[Tanus]

I think 4.10s are perfect, on the highway at like cruising speed @ 70mph, rpms are at like 2k. I dont think it affects mpg much either, my car gets 15mpg (city) with aggresive driving and my car runs low 12s too

 

[ChillPhatCat]

in the city so far my mileage was the same as 3.27s

Yeah I can see that, you have more options for gears in the city than out on the highway, you just shift sooner. On the highway you "run out" of gear more or less.

 

[deftsound]

I have 3.73's and love them, but if i was N/A I would have gone with 4.10's.

 

[Rickyll7]

I think 4.10s are perfect, on the highway at like cruising speed @ 70mph, rpms are at like 2k. I dont think it affects mpg much either, my car gets 15mpg (city) with aggresive driving and my car runs low 12s too

How in the world were you at 2k rpm with 4.10s at 70 mph? do you have a T56 and a 0.50 6th gear?

Gear Ratio Calc

If your turning 2k rpm at 70 mph with stock height tires and a stock tranny, you have stock 3.27 gears.

 

[Tanus]

2k was just an estamate, its definatly under 2,500. I have a really tall rear tire too.

 

[Rickyll7]

2k was just an estamate, its definatly under 2,500. I have a really tall rear tire too.

What is the size of your rear tire?

Even with 275/50/17 tires, you would be over 2300 rpm.

Those tires would look ridiculous by the way.

 

[Tanus]

275/60/15, really tall!

there's a pic in this thread, i like the way the look, just ignore the ****ty 10hole wheels, haha

http://www.stangnet.com/mustang-forums/805041-will-these-fit-295-65r15-bfg-drag-radials-93-fox.html

 

[Rickyll7]

275/60/15, really tall!

there's a pic in this thread, i like the way the look, just ignore the ****ty 10hole wheels, haha

http://www.stangnet.com/mustang-forums/805041-will-these-fit-295-65r15-bfg-drag-radials-93-fox.html

That puts you at just over 2300 rpm at 70 in 5th.